R Plotting

Disclaimer: a lot of the following was taken from Larry Kaplan’s R tutorial at Boston College.

Normal barplot

barplot(table(test2$TestForm))

ggplot2 Barplots

ggplot(test2) +
  geom_bar(aes(x = TestForm, fill = TestForm), color = "black") +
  labs(title = "Test2: test forms",
       subtitle = "2018",
       x = "The 3 test forms",
       y = "Frequencies",
       caption = "figure 16b"
       ) +
  theme(plot.title = element_text(hjust = .5),
        plot.subtitle = element_text(hjust = .5),
        legend.position = "none") + # remove the legend
  scale_y_continuous(limits = c(0, 120)) +
  geom_text(label = "88", x = "a", y = 93) + # put the text at ("a", 93)
  geom_text(label = "99", x = "b", y = 104) +
  geom_text(label = "96", x = "c", y = 100)

ggplot2 Histograms

ggplot(data = test2) +
  geom_histogram(aes(x = Age), 
                     fill = "blue", # fill = ..count..
                     breaks = seq(from = 5, to = 50, by = 5)) +  # x limits
  scale_x_continuous(breaks = seq(from = 5, to = 50, by = 5), # x labels
                     name = "Age of test takers") +
  stat_bin(geom = "text",
           breaks = seq(from = 5, to = 50, by = 5), # labeling each bar
           aes(x = Age, y = ..count.., label = ..count..), vjust = -.3)

ggplot2 Line

ggplot() + 
  scale_x_continuous(limits = c(0,25)) +
  scale_y_continuous(limits = c(0,50)) +
  geom_abline(slope = 1.5, intercept = 8)

ggplot scatter plot

Save the plot

myBarPlot <- ggplot(test2) +
              geom_bar(aes(x = TestForm, fill = TestForm), color = "black") +
              labs(title = "Test2: test forms",
                   subtitle = "2018",
                   x = "The 3 test forms",
                   y = "Frequencies",
                   caption = "figure 16b"
                   ) +
              theme(plot.title = element_text(hjust = .5),
                    plot.subtitle = element_text(hjust = .5),
                    legend.position = "none") +
              scale_y_continuous(limits = c(0, 120)) +
              geom_text(label = "88", x = "a", y = 93) + # put the text at ("a", 93)
              geom_text(label = "99", x = "b", y = 104) +
              geom_text(label = "96", x = "c", y = 101)

setwd("E:/github/blog.lia-yin.com/images")
png("ggplot2.png") 
plot(myBarPlot)
dev.off() # close a plotting device

Save graphs as PDF:

ggsave("mp.pdf", gridExtra::marrangeGrob(grobs = pl, nrow=3, ncol=2))